Rust on my pool wall

[Heartland]

I bought a house last year with an older 24’ round AGP. It was built in the summer of 2001, and it’s now about to enter its 23rd season. I noticed some rust under the return and the skimmer last year when I was inspecting it, but I didn’t think much of it so I put it off. I’m now getting close to opening the pool, and I figure that now is a good time to try to remove the rust and apply a rust inhibitor.

Before I do that, though, I thought it would be a good idea to solicit advice from pool owners with some experience under their belts since I’m pretty new to the game. I’ve attached photos of the rust. Does this look recoverable? My plan was to sand down the rust, then apply a clear Rust-Oleum spray to prevent the rust from spreading. I might repeat the process every year or so depending on its efficacy.

I found a forum post that has me a little worried:
Rusted wall
The rust that OP had on their pool was described as a death knell by fellow forum members, and failure all but inevitable. Whereas OP’s rust spot was actively weeping, though, mine seem to be bone-dry. My rust also appears to be on the surface, as though there were leaks coming from the return and skimmer sometime in the past. The liner was replaced last year by the previous owner, though, so I’m hoping those leaks will be gone.

What are your thoughts? Can I repair this rust and inhibit its spread?

 

[woodyp]

That return rust worries me. I just took down and replaced a half buried AGP. I would NOT assume it's surface only.

I'd drain that pool to a few inches below it and have a look see from the inside before making a determination in regards to it's "sea worthiness".

IT could be the kind of surprise you don't want to be surprised with . The liner itself COULD be what is saving you there. 22 years is a long run.

 

[Heartland]

My pool is currently drained to a few inches below the return line for the winter, so I suppose that now would be as good a time as any to take a look behind the liner.

EDIT: For the life of me, I can’t figure out how to remove the liner from the track without damaging it.

 

[Newdude]

For the life of me, I can’t figure out how to remove the liner from the track without damaging it

Check the bottom of the wiki Here for the basic idea of how it sits in there. Then use tape to gently pull the liner up and away from the grab-y part of the track.

 

[VinnyinNJ]

Be aware that a 22 year old liner is going to be brittle. We had our 20 YO pool liner develop a tear in it, my skimmer and return had similar rust and when I cut the liner to remove it thinking we would just get another liner there was no bottom track left and the walls had developed rust in addition to what was at the skimmer and return. We decided to take it down as I didn't want the pool erupt with no bottom stability.

 

[woodyp]

At the very least I'd say it needed a new return gasket seeing how there is rust Above it.

 

[Heartland]

Check the bottom of the wiki Here for the basic idea of how it sits in there. Then use tape to gently pull the liner up and away from the grab-y part of the track.

Appreciate the advice here. The tape got me further (what a great idea!), but still couldn‘t get the lip to come out of the track, and I’m nervous about applying too much stress to the liner so I gave up on trying to peek beneath it. I’d hate to tear it in the process of fumbling about.

What I might try soon is to remove my return and get a peek behind the liner then. It would also be a prime opportunity to replace the gaskets if need be.

 

[Heartland]

Be aware that a 22 year old liner is going to be brittle. We had our 20 YO pool liner develop a tear in it, my skimmer and return had similar rust and when I cut the liner to remove it thinking we would just get another liner there was no bottom track left and the walls had developed rust in addition to what was at the skimmer and return. We decided to take it down as I didn't want the pool erupt with no bottom stability.

I got lucky there, actually. The previous owner of the house replaced the liner prior to close of sale, so we’ve got a shiny new liner in our older pool.

 

[SecoSteve]

The old owners did you no favors replacing the liner. They just put a band aid on the metal structure. When I took down our AGP, the whole bottom track was rotted beyond repair. And, our pool wall didn't have any noticeable rust on it. I don't think there's any way to salvage the rust.

 

[JoeSelf]

Here are some pics from my tear down. Wish I had taken more. Rust is a killer. 16 years up.

Pools Gone.jpg

• JoeSelf
• Sep 28, 2021

 

[phonedave]

Without getting into a whole mechanics of materials dissertation, the thing to know is that sharp points in materials increase the stress at those points.

It is like when a doctor repairs a meniscus tear. They do not sew up the meniscus, they just cut the end of the tear into a circular shape so it does not tear further.

The round hole for the return is the ideal shape to spread out the stress evenly. However, once it starts rusting and develops a "notch" at the bottom, it will build stresses at that point until they reach a failure point. It is not just the weakening of the material itself from rust, but the stress risers that it creates as well.

 

[Heartland]

You folks really have me going through the stages of grief over here. I think I’m past the denial phase where I insist that it’s just harmless surface rust; from what you’ve all said, this seems to be indicative of a larger issue that will compromise the integrity of the pool over time. I think right now I’m in the bargaining phase; I’m trying to see how long I can keep the pool going before I need to shut it down, disassemble it, and buy a new AGP.

@JoeSelf - That must’ve been heartbreaking to find rust on your pool walls like that. I read the original post. “Thanks, but I no longer need to close. Pool is gone.” You sound so dejected there. Your photos are a good warning at how rust can spread, even if it’s not visible from the outside.

I found a couple of vids on YouTube just now that seem to further illustrate how quickly rust spreads. I was wondering whether I’d find a way to inhibit the rust for a bit, and sure enough, this guy seemed to have the same idea as me: spray with Rust-Oleum in an attempt to mitigate its spread.


Uh, wow. Spoiler alert: the Rust-Oleum did absolutely nothing. Two years later, the pool walls looked like this:


So it seems like a rust inhibitor will have limited effects on steel pool walls, at least in the way it was applied above. I suspect that prepping the surface with a wire brush would have helped a little, but even if I were to assume it fully arrested the rust on the outside, it doesn’t address any rust actively eating away the wall from the inside, nor does it address any structural damage to the wall as @phonedave pointed out.

It sounds like I need to start planning to replace the pool in the not-too-distant future. I’m not ready to give up on the old fella yet, but i’m going to inspect it frequently and take regular pictures of the exterior rust to track spread. When things start looking more bleak, I’ll take it down and order a new one. Putting together a new pool will be a fun project.

 

[Mdragger88]

The good news is that the site work is mostly done with a replacement especially if you can find the same size. When you’re in the pool run your hand over all the walls & feel for anything squishy or bumpy as rust usually bumps up.
You might be able to get a stainless steel repair panel(s) but the pool would need to be drained to install it which may mean a liner replacement & in that case it would be worth just getting an entire replacement pool.

 

[VinnyinNJ]

You folks really have me going through the stages of grief over here. I think I’m past the denial phase where I insist that it’s just harmless surface rust; from what you’ve all said, this seems to be indicative of a larger issue that will compromise the integrity of the pool over time. I think right now I’m in the bargaining phase; I’m trying to see how long I can keep the pool going before I need to shut it down, disassemble it, and buy a new AGP.

@JoeSelf - That must’ve been heartbreaking to find rust on your pool walls like that. I read the original post. “Thanks, but I no longer need to close. Pool is gone.” You sound so dejected there. Your photos are a good warning at how rust can spread, even if it’s not visible from the outside.

I found a couple of vids on YouTube just now that seem to further illustrate how quickly rust spreads. I was wondering whether I’d find a way to inhibit the rust for a bit, and sure enough, this guy seemed to have the same idea as me: spray with Rust-Oleum in an attempt to mitigate its spread.


Uh, wow. Spoiler alert: the Rust-Oleum did absolutely nothing. Two years later, the pool walls looked like this:


So it seems like a rust inhibitor will have limited effects on steel pool walls, at least in the way it was applied above. I suspect that prepping the surface with a wire brush would have helped a little, but even if I were to assume it fully arrested the rust on the outside, it doesn’t address any rust actively eating away the wall from the inside, nor does it address any structural damage to the wall as @phonedave pointed out.

It sounds like I need to start planning to replace the pool in the not-too-distant future. I’m not ready to give up on the old fella yet, but i’m going to inspect it frequently and take regular pictures of the exterior rust to track spread. When things start looking more bleak, I’ll take it down and order a new one. Putting together a new pool will be a fun project.

I didn't watch the videos but I believe the compound that can stop/convert rust to neutralize it needs to be painted over it for it to stay good; if done inside the pool wall nobody will see it. I've seen that rust conversion done on car videos and people claim it lasts as long as it's painted over. I've also seen videos where people make a panel out of aluminum to screw it onto the pool wall for the skimmer and return - I can't say what I saw actually works though. All the aluminum I've played around with (not much at that) is thin duct aluminum. It may be possible the pool's wall is kind of OK except at the skimmer and return but I would be concerned about the bottom track where the pool wall sits into; my bottom track was totally gone meaning the bottom of the up rites were no longer tied into anything. They were only connected to the pool by the top rail. I was shocked that mine was totally gone.

Also, it looks like you have rocks around the pool - do yourself a favor and take the rocks away from that area before removing that pool wall if you're going to replace it. Our pool was gone for 3 years so maybe that had a big effect but I had to sift the sand that was already down to get rid of the rocks that migrated into the sand ... it's easier not to get rocks in the sand area with a barrier in place.

 

[JoyfulNoise]

Rust-o-luem will do nothing for you. In order to "restore" a steel surface, there has to actually be metal left to restore. Iron oxidizes through a process of consumption - oxygen reacts with iron to form iron oxide. The oxide has a completely different crystalline structure relative to the original metal material and therefore undergoes significant volumetric expansion leading to fractures and spalling. There is also an Fe2+/Fe3+ redox reaction that occurs that catalyzes and accelerates the oxidation process. Rather than being "self-limiting" as is the case with aluminum and titanium metals (both of which are much more reactive with oxygen than iron), the iron oxidation reaction is self-consuming - like a lite fuse it continues to burn until the entirety of the metal is consumed.

The only way to stop the reaction is to carefully clean off ALL of the oxide that forms and then apply a chemical inhibitor such as chromate or phosphate that will scavenge any oxidizers and form a protective barrier layer on the surface of the iron metal. Naval Jelly (no, not your belly button ... naval as in you're in the Navy now!) is a thick phosphate compound that is used to restore iron oxidation by reacting with any iron oxide on the surface and then forming a bound iron phosphate layer that is protective against oxidation. Once the naval jelly is applied, you can then paint over the metal surface. Chromate conversion coatings (either chemical or electrochemical) are another iron sealing process that protects the surface and makes it paintable. However, none of that works if the iron is completely rusted through. Galvanizing is another process for sealing iron surfaces but it is also sacrificial in nature and will not last forever.

 

[Heartland]

Rust-o-luem will do nothing for you. In order to "restore" a steel surface, there has to actually be metal left to restore. Iron oxidizes through a process of consumption - oxygen reacts with iron to form iron oxide. The oxide has a completely different crystalline structure relative to the original metal material and therefore undergoes significant volumetric expansion leading to fractures and spalling. There is also an Fe2+/Fe3+ redox reaction that occurs that catalyzes and accelerates the oxidation process. Rather than being "self-limiting" as is the case with aluminum and titanium metals (both of which are much more reactive with oxygen than iron), the iron oxidation reaction is self-consuming - like a lite fuse it continues to burn until the entirety of the metal is consumed.

The only way to stop the reaction is to carefully clean off ALL of the oxide that forms and then apply a chemical inhibitor such as chromate or phosphate that will scavenge any oxidizers and form a protective barrier layer on the surface of the iron metal. Naval Jelly (no, not your belly button ... naval as in you're in the Navy now!) is a thick phosphate compound that is used to restore iron oxidation by reacting with any iron oxide on the surface and then forming a bound iron phosphate layer that is protective against oxidation. Once the naval jelly is applied, you can then paint over the metal surface. Chromate conversion coatings (either chemical or electrochemical) are another iron sealing process that protects the surface and makes it paintable. However, none of that works if the iron is completely rusted through. Galvanizing is another process for sealing iron surfaces but it is also sacrificial in nature and will not last forever.

Thank you for the detailed breakdown of corrosion across different metals! This is exactly the knowledge I needed to combat the rust, at least for a little longer until I can more readily afford a new pool. So it sounds like the process would be as such:
1. Prepare the surface by removing as much rust as possible. A wire brush would probably be good here.
2. Apply naval jelly to the surface to react with any remaining rust and form a protective layer.
3. Paint over the (hopefully) neutralized rust to prevent further oxidation. I might try a clear coat here so that I can still monitor the surface in case the rust returns.

@VinnyinNJ, thanks for bringing up the bottom track; I didn’t even think to check that. I’ll see if I can get to it below the soil to check its health. And thank you for the tip about the rocks around the pool!

When I do end up replacing the pool, I’m taking a good look at the Saltwater Aurora resin pool. Not having to worry about rust sounds like a luxury, and the build thread below looked promising:

Saltwater Aurora all-resin pool build thread!

I hadn’t checked in a while to see if the one I wanted was back in stock, and it is! I just ordered. Haven’t decided on pump/filter yet. Pool weather comes soon around here, and I want to get this thing installed before it gets too hot!

www.troublefreepool.com

 

[kimkats]

I did the whole wire brush/wheel thing on the inside of my pool. We got a new liner and in pulling down the old liner found there was rust all over the inside of the pool with none seen on the outside. I also applied all of what you are thinking of using. The pool lasted another few months. What happened is where the pool walls met the rust ate through the metal and it let go in the middle of the night. Woke up to the results of a "title wave" from the water rushing out. Thankfully there was a lot of room for the water to flow without doing any damage to the house or porch.

Start saving your dimes now. I would not touch any of the rusted area as I fear it will weaken that area causing more harm than good down the road.

 

[Newdude]

When I do end up replacing the pool, I’m taking a good look at the Saltwater Aurora resin pool. Not having to worry about rust sounds like a luxury, and the build thread below looked promising:

If I was going through the trouble of installing an above ground pool, once would be enough with me. The days of steel pools lasting decades are long gone. Kelly and those that have gotten the Aurora or equivalent have been real happy with them.

Also look at the aquasport style coated aluminum pools for a similar price. Mine came out in perfect condition 17 years later. (Albeit dirty. Lol)

 

[JoeSelf]

@JoeSelf - That must’ve been heartbreaking to find rust on your pool walls like that. I read the original post. “Thanks, but I no longer need to close. Pool is gone.” You sound so dejected there. Your photos are a good warning at how rust can spread, even if it’s not visible from the outside.

This was the last year for it, so I was prepared. We had a paver patio put in in its place and got a Hot Tub. We can use it year round now!